Oil burner



April 29, 1.9414. M L MUELLER 2,240,161 Y on. BURNER l l Filed Nov'.- 5. 195s V EL 1N VENTOR .n ,Patented Apr. y29, 1941 'UNITED s'rrras PATENTl ori-"Ici:

Y on. BURNER Moritz L Mueller, Grosse Pointe, Mich., assignor to Borg-Warner Corporation, Chicago, Ill.,

l corporation of Illinois Application November 5, 1938, Serial No. 238,981

. (Cl. 158i-4) 3 Claims.

vThis invention relates to oil burners, more particularly to pressurel oilk burners, and has special reference to an expansion chamber for accommodating sudden increases in pressure.

It is an object of 'this invention to provide a novel form of pressure oil burner which will be safer in operation.

It is another object of this invention to provide an oil burner which will be free from back-liring and the evil known as flutter draft.

It is another object of this invention to provide a baille for a pressure oil burner, which is adapted to accommodate sudden increases in pressure in the combustion chamber due tothe sudden ignition of a quantity of oil and air.-

My invention deals with a new combustion chamber -head for oil burners. The'device comprises two spaced walls through which the burner mouth is inserted. The inner one of these two walls does not tightly embrace the burner mouth so as to provide a passageway around the burner through which the rapidly expanding products of j combustion at the initiation of combustion may pass, to relieve the pressure caused by the sudden ignition of the oil and air. In order for this to take place, the outer wall has vents to the at- Y Vmosphere, so that, some of the air which is between the two walls will be pushed out into the atmosphere when the burner is started. After conditions are stabilized, the products of combustion which-have expanded into the space between the two heads are drawn back into the burner by the slight suction which will exist within the combustion chamber.` During the continuation of combustion, a small supply of air will be sent into the combustion chamber through the aperture in the outer wall of the double head and around the burner mouth.

The drawing which illustrates my invention, of which there is one sheet, may be generally described as follows:

Fig. 1 is a vertical section through an oil burning furnace embodying my invention;

Fig. v2 represents an enlarged view of a portion of the combustion'chamber shown in Fig. 1,

the view being in vertical section to illustrate the relation of the parts; and

Fig. 3 represents an elevation of the combustion chamber head and is a View taken along the section line 3+3 of Fig. 2.

As illustrated in Fig. 1, my oil burner consists of a casing I0 of any suitable metal construction which. encloses a blower compartment I2, an oil burner compartment I4, a combustion chamber I6. and a `heat exchange chamber I 8. The

Cabinet has an opening 26 in the top thereof, through which air is supplied to the blower chamber, and an opening 22 in the top, through which) warm air is directed into the heating system of the house. 'I'he cabinet may be provided with a door 24, through which access may le had to the blower or oil burner for servicing the same. Theoil burnerl compartment I4 is. separated from the vblower compartment I2 by a partition 26 and contains an oil lburner 28 of the pressure type, having aburner mouth 30 extending into the combustion chamber I6. The oil burner may be supported on legs 32 to maintain it at the correct height above the bottom of the furnace. The partition 26 supports a blower 34and a motor 36 for operating the blower which directs air intov the heat exchange compartment I8.

The heat exchange chamber I8 contains an annular fiue 3l dened by an outer cylinder 38 e and an inner cylinder 39. 'I'he flue is attached to the combustion chamber I6 at 49 and contains the' spiral baille 42, which directs the products of combustion in a spiral path through the annular ue, as is indicated bythe wide line arrows. The smoke pipe 46 is attached to the ue at its upper end and directs the products of combustion from the iiue through the casing I Il and to the stack (not shown). The nue 31 is supported on the combustion chamber by the neck 46 which forms a connection with the combustion chamber and by a bracket 48 which supports the opposite side of the flue. 'Ihe foregoing structure is disclosed 'and claimed in my Patent No. 2,172,399, issued September 12,' 1939.

The combustion chamber I6 is composed of a metal cylinder 50 and contains a flame chamber 52 composed of blocks of refractory material 54.

The combustion chamber I6 may also contain a connection 56 for a hot water heating coil 58. The

Icylinder is supported above the oor of the furnaceby legs 66, so that the' blast of air from the blower 34 may'pass around and underneath the cylinder 5U. In operation, the air from the lblower 34 takes a spiral path around the outside of the ue 31, and after passing down and around the cylinder 50, passes up and through the centerl flame chamber 52. The flame chamber 5,2 is composed of a horizontal metal cylinder 63, lined with the refractory material 5I. The forward end of the flame chamber is closed by a disc of refractory material i4, having a hole 66 in the center thereof. The head for the cylinder 50 is composed of a metal disc 68, which is fastened to the cylinder 5I by the clips 10, which are bolted to the cylinder 50. The clips 'I0 may be fastened to the disc 68 by any suitable means, such as welding. 'I'he disc 68 has a hole which is in alignment with the hole 66 in the forwardend of the v llame chamber and through which the burner mouth 30 is adapted to be inserted. An annular bracket 12 may be bolted around the hole inthe disc $8 for the purpose of maintaining the burner mouth Il in its correct position. Fastened to the side of disc il toward the inside of the combustion chamber is a second plate 16, which is sphericall in -shape and is drawn down tight against the plate i! by means of the bolts 1l.

'I'he spherical plate 16 has a circular flange 'Il raised from its back side in such a manner that the plate may be sealed against the end of the llame chamber, thus forcing any gases which pass through the hole 66 to pass through the hole .Il in the spherical plate 16. Both the hole 6i and the hole Il are of larger diameter than the burner mouth 30, which passes through both holes and thus leaves an annular passage around the burner mouth, between the name chamber 52 and the space between the head plates 62 and 16. This space between the two plates is open to the atmosphere of the oil burner chamber il through two ports l2, which may be closed or regulated by the dampers 84 bolted to the plate' il. It should be noted that the contacts between the plate B8 and the combustion cylinder il are sealed so that no gases may pass therebetween. There is also a sealed connection between the plate i8 and the plate 1i and between the plate 'I6 and the head of the llame chamber, where the burner mouth passes through those members. The burner mouth is also` sealed to the plate il, where it passes through the plate. In this manner, the only passage for gases between the combustion chamber and the atmosphere of the oil burner chamber is through the hole 66, hole 8l, and then through the ports l2.

In operation, the oil burner 28, which may be any conventional pressure type burner and which I have illustrated as having a burner head 86 and nozzle 88, will pump a stream of finely divided oil and air into the name chamber 52. The mixture may be ignited byV any means such as the electrodes 9B. Just before ignition takes place, there will be a relatively small pressure in the flame chamber. At'the time of ignition, there will be a sudden increase in the pressure within the combustion chamber and flame chamber, due to the sudden expansion of this mixture of oil and air. This increase in pressure may work its way out partly 'through the nue 31 and partly through the holes 66 and 2l into the space between the plates it and 1G. The air within the space between 5 the head plates may4 escape through the ports l2, thus relieving the suddenly increased pressure within the combustion chamber. The space between the plates 6I and 10 may be made large enough so that no gases will be forced out of the ports 82, the only displacement being that of the air that is already in the space between the two plates. As soon as the combustion is well started, the blast from the burner mouth and the draft created by the warm gases in the combustion chamber will draw all of the gases out of the dame chamber into the combustion chamber proper and out through the annular' flue 21, and there 'will be no tendency for the burning gases to escape through the head of the combustion chamber. Avsmall supply of secondary air may even be drawn in through the ports 82 and through the passage 66 around the burner mouth, due to the draft set up in the combustion chamber. This arrangement of parts allows for the sudden expansion of gases, due to ignition, in the combustion chamber without the necessity of a complicated system of expandible chambers or expansion valves.

such changes in the structure as will fall within p the purview of the attached claims.

I claim:

1. In combination with a furnace having a combustion chamber and a pressure oil burner operatively associated th'erewith and adapted to supply a combustible mixture of oil and air to said combustion chamber, la pair of heads constructed and arranged so as to denne an expansion chamber and'situated so as to close one end of said combustion chamber, a restricted communication between said chambers independently of said oil burner, said expansion chamber having a port communicating directly with the atmosphere outside of said oil burner and said com bustion chamber.

2. In combinationgwith a furnace having a A combustion chamber and a pressure oil burner operatively associated therewith and adapted to supply a co bustible mixture of oil and air to said combust on chamber, an expansion chamber formed in part by a wall of said combustion chamber, a restricted communication between said chambers independently of said oil burner, said expansion chamber having a port remote from said restricted communication and communicating directly with the atmosphere outside of said combustion chamber.

3. In combination with a furnace having a combustion chamber and a premura oil burner operatively'associated therewithand adapted to supply a combustible mixture of oil and air to said combustion chamber, a head cooperating with a wall of said combustion chamber so as to define an expansion chamber, a part of said burner extending through said expansion chamber, a restricted communication externally oi' said part of said burner and between said chambers, `said expansion chamber having a port communicating directly with the atmosphere outside 5 of said combustion chamber.

MURITZ L. MUEILER. 

